We describe ${\tt ipole}$, a new public ray-tracing code for covariant,
polarized radiative transport. The code extends the ${\tt ibothros}$ scheme for
covariant, unpolarized transport using two representations of the polarized
radiation field: in the coordinate frame, it parallel transports the coherency
tensor; in the frame of the plasma it evolves the Stokes parameters under
emission, absorption, and Faraday conversion. The transport step is implemented
to be as spacetime- and coordinate- independent as possible. The emission,
absorption, and Faraday conversion step is implemented using an analytic
solution to the polarized transport equation with constant coefficients. As a
result, ${\tt ipole}$ is stable, efficient, and produces a physically
reasonable solution even for a step with high optical depth and Faraday depth.
We show that the code matches analytic results in flat space, and that it
produces results that converge to those produced by Dexter's ${\tt grtrans}$
polarized transport code on a complicated model problem. We expect ${\tt
ipole}$ will mainly find applications in modeling Event Horizon Telescope
sources, but it may also be useful in other relativistic transport problems
such as modeling for the IXPE mission.

描述了一个用于公共射线追踪的代码 ${t ipole}$，用于协变极化辐射传输。该代码使用极化辐射场的两种表示方式扩展了用于协变非极化传输的 ${t ibothros}$ 计划。我们向平行传输一致性张量和在等离子体框架下使用解析解决定 Stokes 参量的演变过程。我们证明了该代码与相应的分析结果匹配，并且在具有高光学深度和 Faraday 深度步骤的情况下产生出物理合理的解。